A respirator with a breathing filter, which is displaceable within a breathing connection and is connected to the mask body via a bellows has become known from DE 40 20 127 C1. The bellows surrounds the breathing filter in the form of a cuff and seals the interior of the mask in the area of the breathing filter against the environment. A guide ring made of a solid material is used to push the breathing filter into the interior of the mask together with the cuff. The guide ring is provided within the breathing connection. The cuff slides along the inner side of the guide ring. To improve the sliding properties, the cuff is provided, in the manner of a sleeve, with a sliding strip made of Teflon. To fix the breathing filter in the position of use, a sealing lip, which presses the outside of the cuff on all sides, is arranged on the breathing connection.
The disadvantage of the prior-art respirator is the fact that it is not possible to recognize from the outside whether the breathing filter has been completely pushed out of the mask body. Even though the length of the pushing movement is limited by the bellows, an impact on the breathing filter may cause the breathing filter to be partially displaced in the direction of the interior of the mask before the respirator is put on. This is because the fixation of the breathing filter in the position of use depends essentially on the force of the pressure of the sealing lip at the breathing connection on the cuff of the breathing filter. Moreover, the prior-art respirator is expensive to manufacture, because the sliding ring and the sliding strip also must be mounted on the rubber molding of the mask body.